Stock-Based Compensation (Details) - USD ($)	3 Months Ended		9 Months Ended
	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2022	Jan. 31, 2021
Share-based Payment Arrangement [Abstract]
Option to purchase common stock (in shares)			1,438,500	1,340,000
Stock-based compensation expense	$ 1,100,000	$ 700,000	$ 2,910,000	$ 1,901,000
Income tax excess benefit	326,682	$ 232,882	$ 1,900,000	$ 500,000
Stock options exercised (in shares)			678,129	462,321
Total intrinsic value of options exercised			$ 9,100,000	$ 2,800,000
Unrecognized compensation cost related to unvested stock option	$ 13,100,000		$ 13,100,000
Weighted average period for unrecognized compensation cost			2 years